This invention relates generally to article grouping systems capable of forming discrete groups of articles so that these article groups can be loaded into upwardly open packing cases, and deals more particularly with a grouper of the pin type having upstanding pins for entry between adjacent round articles in a line or column of articles. A predetermined number of the articles are first trapped between a pair of pin sets that serve to continuously hold back the line of articles as each group of articles is selected for release. The leading pin set moves downwardly out of the path of the articles and a second pin set holds back the articles in the line.
Prior art systems for grouping articles have generally taken the form of two sets of pins on separately controlled chain conveyors that are driven at variable speed. See, for example, Pat. No. 4,552,261 entitled ARTICLE GROUPER FOR A CASE BACKER and assigned to the assignee herein. In the '261 Patent, the variable speed is provided for in the form of a differential drive between the two pin sets.
In a later adaptation of that invention, two separate pin conveyors are driven at variable speed by separately controlled servo motors that serve essentially the same purpose as that of the variable speed drive in the '261 Patent. See, for example, Pat. No. 5,065,856.
The general purpose of the present invention is to provide for a constant speed drive to the two sets of pin conveyors so that each article group is first segregated between these pin sets and released for acceleration by a third pin set downstream of the pair of pin sets referred to previously. Such a system provides product grouping into a conventional flight bar system capable of controlled movement of each group of articles into and through the load station in accordance with conventional practice.